I have voted for the Democratic candidate in every election since the 1980s. This includes Bill Clinton twice and Hillary once (although for that last one, I held my nose).
Like every other good liberal I believed in Bill Clinton. I was young, naive and fanatically liberal back then. There were rumors about Bill's behavior toward women from the moment he burst onto the national scene, including rumors about harassment and assault. These stories started well before his presidential run. Everyone one of them were explained away.
Then came the wagging finger where Bill Clinton looked me in the eye and said he had no "sexual relations with that woman". Then came the indisputable cold hard facts including DNA on a blue dress that made it clear that Bill Clinton lied (at least this one time). For me this made all of the other denials, from woman after woman, seem a lot more suspicious.
The blue dress... discovering that Bill Clinton lied and that he had in fact had oral sex with a junior employee in the Oval Office.... was a big moment in my personal political evolution.